ruby_version_check_beta.rb

def patch_level_compare(v1, v2)
   v1_ruby_v, v1_patch_level = ruby_version_split(v1)
   v2_ruby_v, v2_patch_level = ruby_version_split(v2)

   if v1_ruby_v == v2_ruby_v
      if v1_patch_level == v2_patch_level
         return 0
      elsif v1_patch_level > v2_patch_level
         return 1
      else
         return -1
      end
   elsif v1_ruby_v > v2_ruby_v
      return 1
   else
      return -1
   end
end

def ruby_version_split(v_str)
   vers = v_str.tr("-p",".").split(".").delete_if { |i| i.size == 0 }.map { |i| i.to_i }

   patch_level = vers.pop
   ruby_ver = vers.each_with_index.map { |x, i| x.to_i * 10 ** (5 - i) }.inject { |sum, i| sum + i }

   [ruby_ver, patch_level]
end

p patch_level_compare("1.9.3-p123", "1.9.3-p123") # => 0
p patch_level_compare("1.9.3-p124", "1.9.3-p123") # => 1
p patch_level_compare("1.9.3-p123", "1.9.3-p124") # => -1

p patch_level_compare("2.0.0-p0", "1.9.3-p124") # => 1
p patch_level_compare("1.9.3-p123", "2.0.0-p0") # => -1